316 



LOWER IN VER TEBRA TES. 



The sub-family AcLatininae embraces forms miieh like the Helicina; but distinguished 

 by lingual dentition and by the fact that the lip is usually sharp, the columella trunca- 

 ted, the shell with an elongate spire, the body whorl being swollen. The genus Achu- 

 tina, the agate shells, derives its name from the usually banded species. It embraces 

 the largest species of iiulraonates known, even exceeding the genus ^(«//w«s in this re- 

 spect, as some of the shells measure ten inches in length. The eggs are of 2)roportion- 

 ate size and have a calcareous shell. Most of the species are found in Africa, where 

 they live in trees, descending to the ground to lay their eggs. 



In tlie genus Achatinelhi, the dextral or sinistral shell is much like that of JBulimus 

 in outline, but is distinguished among other characters by the spiral fold which accom- 

 jianies the columella. The species are coniined to the Haw.iian Islands, but their num- 

 ber lias been nmltiplied to an utterly unwarranted extent, no less than tlii'ee hundred 

 having been described. All are very i)retty shells, with a jiolished exterior, and striped 

 and spotted with liright colors, red, green, and Virown ])rc<l(iminating. We well know 



- Pupa 



Fig. 38U.— Pupa 

 pttitoflon. 



Fig. 382. — p{ij}a 

 fa/lax. 



how inconstant is the number of bands in the land shells of the United States, where 

 the same s])ecies may be plain or oi-namented with one or several spiral bands, but 

 these Acliatinelhe have been divided up mostly on similar characters. They live 

 largely on the low shrulibery near the sea, but since the introduction of cattle on the 

 islands they have become much less common than formerly, on account of the destruc- 

 tion of their food plants; and their ultimate extinction is but a question of time. 



In the PuPiDJE, we have a large number of generally small, many whorled, more or 

 less cylindrical shells, in which the aj.erture is frequently contracted by tooth-like 

 processes, like those previously described in some of the Helices. Our American 

 species of Pj/^/(( are almost all very minute, so that it requires good eyes to collect 



Fig, .■iss. _ rertigo Fig. 3S-}. — Verfirio 



Fig. 387. — Ff 

 s'nnplex 



them. They seem to be even more dependent on moisture than most other land 

 shells. The species are lar<>-ely based on the number and form of the teeth of the aper- 

 ture, the variations in which may be seen in our figures of some of the more common 

 species from the United States. One of the most important distinctions between 

 Vertiffo and Pupa lies in the fact that in the latter genus the cephalic tentacles are 

 jiresent, though small, while in the former they are absent. 



The genus Clausilia occurs in the regions surrounding the Mediterranean, its 



